The present invention relates to a gas control unit for a boiler, and more particularly, to a gas control unit for a boiler which can satisfactorily supply and shut off gas and which is not in danger of gas leakage.
In general, a boiler is an apparatus that heats water using combustion heat generated in combusting a fuel and supplies heated water or steam to necessary places. Boilers are classified into household boilers and industrial boilers depending on uses thereof, are classified into small-capacity boilers used at home or the like and large-capacity boilers used in power plants or the like depending on capacity thereof, and are classified into oil-fired boilers and gas-fired boilers depending on fuels to be used.
In the gas-fired boilers using gas as a fuel out of the boilers, sparks are generated to ignite using an ignition transformer and an ignition rod and supplied gas is combusted to heat water. Such gas-fired boilers should adjust an amount of gas to be supplied depending on an amount of inflow air, for the purpose of perfect combustion of the gas.
On the other hand, a gas control unit adjusting the amount of gas to be supplied depending on the amount of air is electromagnetically controlled to supply an appropriate amount of gas depending on the amount of inflow air. That is, a sensor disposed in an air inlet through which air flows in senses an amount of inflow air and transmits the sensed result to a controller such as a microcomputer, and the controller supplies gas so as to correspond to a predetermined mixing ratio depending on the amount of inflow air. For example, the amount of gas to be supplied is controlled to increase when the amount of air to flow from the outside is large and the amount of gas to be supplied is controlled to decrease when the amount of air to flow is small, thereby keeping the mixing ratio of gas and air constant.
The invention relates to a gas control unit that is disposed in a boiler and that controls an amount of gas to be supplied depending on an amount of air. Referring to the prior art (Korean Patent Publication No. 10-2010-0001600, registered on Dec. 23, 2009), a valve according to the prior art has the following problem.
First, the valve according to the prior art has a structure in which a degree of opening of a gas outlet depending on the depth by which a gas discharge control section is inserted into the gas outlet. Accordingly, when the center of the gas discharge control section and the center of the gas outlet slightly depart from each other, it is not easy to control the degree of opening of the gas outlet. Particularly, when a manufacturing tolerance or an assembly error occurs between the outer diameter of the gas discharge control section and the inner diameter of the gas outlet, it is not easy to shut the gas outlet.
Second, the valve according to the prior art has a structure in which a diaphragm for preventing gas leakage is inserted into and fixed to an attachment groove of the gas discharge control section. Accordingly, when the gas discharge control section is often shifted, the diaphragm inserted into the attachment groove may be in danger of departure. In this case, gas may leak to cause a safety accident.